This study involved interviews with 200 phencyclidine users. The research design included interviews with heavy and lighter chronic users as well as a group of recreational users. Respondents were obtained through local drug using contacts and snowball sampling techniques were used. The objectives of the research are to: 1) examine patterns of use and change in use patterns, 2) describe the perceived motivation for use, reason for quitting, and perceived effects of phencyclidine, and 3) determine health and behavioral changes in the user that are related to phencyclidine use. Data analysis will begin in March, 1980.